This invention relates to a photocurable and photopatternable composition comprising a photocrosslinker and a polymer having azlactone functionality. The composition may be patterned with high resolution on a substrate and used to bind biologically active molecules.
Various methods for immobilizing biomolecules to substrates have been disclosed.
U.S. Pat. No. 5,552,270 concerns a method of DNA sequencing wherein DNA oligonucleotides are immobilized in a matrix of gel squares which are supported on a substrate. The DNA is bound to the substrate by oxidation of an added 3xe2x80x2 terminal 3-methyl uridine followed by reaction with a substrate-bound hydrazine to produce xe2x80x9ca relatively stable morpholine derivativexe2x80x9d. (""270 at col. 5, lns. 41-47). The reference discloses gel squares that are between 25 and 100 xcexcm on a side and are separated by spaces twice as wide. (""270 at col. 2, lns. 60-64).
U.S. Pat. No. 5,744,305 concerns a biological chip plate that includes DNA or peptide oligomer patches synthesized in situ by xe2x80x9clight-directed synthesisxe2x80x9d, where protective groups are selectively removed prior to each monomer addition step by a light reaction using a mask. The initial base of each oligomeric strand is apparently bound to the substrate by attachment to an amine function. (""305 at FIGS. 1 and 2).
U.S. Pat. No. 4,871,824 concerns low-swelling beads of azlactone-functional polymers for use as reactive supports for immobilization of biologically active molecules.
U.S. Pat. No. 5,344,701 concerns methods for immobilizing biomolecules on substrates by attachment to azlactone-functional coatings. This reference discloses the application to a substrate of azlactone-functional monomers having free-radical addition sites, optionally with a free-radical crosslinker such as a divinyl, and subsequent polymerization in situ.
U.S. Pat. No. 5,725,989 concerns a laser addressable thermal transfer imaging element that comprises a support, a light-to-heat conversion layer, an interlayer, and a thermal transfer layer.
Briefly, the present invention provides a photocurable and photopatternable composition comprising a) at least one copolymer derived from and 1 to 99 parts by weight of at least one azlactone-functional monomer and 0 to 99 parts of at least one co-monomer; and b) at least one photocrosslinker; wherein the composition may be used to bind biologically active molecules.
In another aspect, the present invention provides a hydrogel comprising the cured composition of the invention, where the gel is capable of binding biologically active molecules. The gel advantageously is swellable, thus providing a greater concentration of biologically active molecules per unit area when used as a coating.
In another aspect, the present invention provides a substrate coated with the composition of the invention, where the composition is capable of being patterned to a high resolution, which may be cured, and where the composition is capable of being reacted with biomolecules to immobilize the biomolecules on the substrate.
In another aspect, the present invention provides methods of making the coated substrates described above.
What has not been described in the art, and is provided by the present invention, is a composition and method useful for immobilizing biomolecules that employs azlactone-functional polymers in combination with photocrosslinkers. Furthermore, the composition of the present invention may be photopatterned with high resolution. Finally, the resulting cured gel preferably is swellable, providing a greater concentration of biomolecules per unit area.
In this application:
xe2x80x9cazlactone,xe2x80x9d xe2x80x9cazlactone functionxe2x80x9d, and xe2x80x9cazlactone moietyxe2x80x9d mean substituted or unsubstituted 2-oxazolin-5-one groups of Formula I and/or 2-oxazin-6-one groups of Formula II: 
xe2x80x9cazlactone-functional monomerxe2x80x9d means a monomer whose structure includes an azlactone moiety, which optionally has been bound to a biomolecule by a ring opening reaction of the azlactone to form a biomolecule-azlactone bond;
xe2x80x9chydrogelxe2x80x9d is a polymeric material capable of swelling in water by either physical interaction such as adsorption or absorption or chemical interaction such as hydrolysis, and refers to the gel material either before or after swelling in water;
xe2x80x9cphotocrosslinkerxe2x80x9d means a chemical species that is capable of binding two or more polymer molecules in response to the application of electromagnetic radiation and capable of attaching to the polymer molecules at a site other than the end of a growing polymer chain;
xe2x80x9ccopolymeric crosslinkerxe2x80x9d means a chemical species that is capable of binding two or more polymer molecules and that attaches to a polymer at the end of a growing polymer chain;
xe2x80x9cbiologically activexe2x80x9d includes biochemically, immunochemically, physiologically or pharmaceutically active;
xe2x80x9cbiologically active moleculexe2x80x9d and xe2x80x9cbiomoleculexe2x80x9d are used interchangeably and include antibodies, antigens, enzymes, cofactors, inhibitors, hormones, receptors, coagulation factors, amino acids, histones, vitamins, drugs, cell surface markers, proteins and polypeptides, DNA including DNA oligonucleotides, RNA including RNA oligonucleotides, PNA, and derivatives of the foregoing; and
xe2x80x9csubstitutedxe2x80x9d means substituted by conventional substituents which do not interfere with the desired product, e.g., substituents can be alkyl, alkoxy, aryl, phenyl, halo (F, Cl, Br, I), cyano, nitro, etc.
It is an advantage of the present invention to provide a composition and method useful for immobilizing biomolecules to a substrate that is applicable to a wide variety of biomolecules and may be photo-patterned with high resolution.